Balanced slide-valve



'UNITED STATES PATENT OFFICE.`

JOHN SLOAN, OF PIT'ISBURG, PENNSYLVANIA.

BALANCED SLIDE-VALVE.

Speccation of Letters Patent No. 27,011, dated January 31, 1860.

' the manner herein after described.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

In the accompanying drawings Figure l, is a side view of the engine.Fig. 2, is a top view of the engine with the cap of the steam chestremoved. Fig. 3, represents a cut or sectional view of the cylinder,steam chest, slide valve, receiving and exhaust openings and pipes. Fig.4, is a cut or sectional view of the cylinder', steam chest and slidevalve, and represents one of the steam ports which lead into thecylinder, also one of the openings in the slide valve, and one of thesteam chambers in the cap of the steam chest. Fig. 5, is a perspectiveview of the valve.

(a) is the base upon which the engine rests.

(o) is the cylinder.

(y) are the flanges on the ends of the cylinder.

(CZ) are the lugs of the cylinder and are used for bolting it down onthe base (a).

(o) is the steam chest, (c) is the piston rod which is furnished with anarm (f) which is used in connection with the fianges (g) on the rod (it)for the purpose of op erating the slide valve (a2). The guides orbearings of the piston rod (e) and valve rod (Zz.) are in the stand(2').

(o) is the valve seat which is furnished with two guides (2 and 3).

(a) is the case which forms the sides and ends of the steam chest.

(m) is the cap of the steam chest and is furnished with a steam chamberat each end directly over the steam ports (s) of the cylinder. 'Thesteam chambers (Z) in the cap (m) of the cheam chest are used for thepurpose of balancing the slide valve (zo) which is furnished withopenings (r) which form a steam passage between the steam ports (s) ofthe cylinder and the steam chambers (Z) in the cap of the steam chest.

The valve and its chamber are made wedge shaped. The 4upper surface ofthe valve is covered by the cap (m). The thick side of the valfe on theinside is furnished with a projection (l) which has an opening (u)through it and the side of the valve. This opening is used for thepurpose of cutting away a portion of the projection (l) so that it willware away equally with the upper and lower surfaces of the valve,thereby allowing the valve to seat itself by its own action; and theopening (u) also relieves a part of the thick side of the valve from theaction of the steam in exhausting from the cylinder, thereby equalizingthe pressure of steam on the outside ends and sides of the valve. Theprojection (l) on the inside of the valve and the guide (2) protects aportion of the thick side of the valve on the inside from the action ofthe steam when receiving, thereby making the pressure of steam equal onthe inside ends and sides of the valve. The valve is relieved from theupward pressure by the chambers (Z) which are made equal in size to thesteam ports (s) leading into the cylinder, the steam from the port (s)causing the upward pressure, passes through the opening (-r) into thechamber (Z) in the cap, thereby balancing the valve by thus relieving itfrom the upward pressure of steam in the cylinder.

(o) is the exhaust opening.

(p) is the exhaust pipe.

is the steam pipe which connects with the steam boiler.

(r) is the receiving or supply opening.

(4) is a staple into which the rod (71,) is hooked. It will be observedthat the pipe (j) and the opening (r) can be used for the purpose ofexhaust-ing the steam, and the pipe (2)) and the opening (o) can be usedfor the purpose of supplying the cylinder with steam.

W'hen the slide valve and the other parts of theengine are in theposition represented in Fig. (2) the back end of the cylinder will bereceiving steam and the front end of the cylinder will be exhaustingsteam. Now by moving the piston (c) forward toward the stand theprojecting arm will come in contact with the forward flange (g) on therod (h) and move the valve forward until it passes the forward port (8);the

forward end of the cylinder Will then be receiving steam andthe back endWill be eX-V hausting steam.

Having thus described the nature,v construction, and operation of myimprovement, what I claim as of my invention and desire to secure byLetters Patent of the United States isl. The use of the Wedge shapedslide valve in combination With the steam chest, said steam chest beingadapted in form and size to the form and size of the valve as hereindescribed and set forth.

2. The use ofthe projection `(i), and opening When used inV connectionWith 15 the guide and guard (2) as herein described and for the purposeset forth.

3. The use of the openings (1") in the valve when used in connectionWith the. steam chambers (l) in the cap (m) and 20 the steam ports (8')of the cylinder; as herein described and for the purpose set forth.

JOHN .SLOAN Witnesses:

JAMES J. JOHNSTON, GEORGE P. GRECE.

